Combine ingredients in a stock pot and bring to a boil.
Reduce heat to low and simmer until vegetables are soft, about 30-40 minutes.
Use a stick blender or high powered blender to blend ingredients into a smooth sauce.
Rinse liver and place in a bowl of water. Add 1 tsp fresh lemon juice and allow to sit for about 20 minutes. This improves the taste.
While the vegetables are simmering for sauce, add ingredients to a large, deep skillet and cook on medium-low until meat is brown and cooked through. If the stock cooks out, add more to be sure everything is cooking in stock and not frying.
Once you've blended your sauce and your beef is cooked, add the sauce to the beef mixture and stir well.